In view of increasing global energy demand and finite resources of fossil fuels, photovoltaic devices are receiving a great deal of attention. Solution-processable organic semiconductors represent a promising class of new organic photovoltaic (OPV) materials with potential for low manufacturing costs and applications ranging from flexible and mobile devices to large-area installations.[1] In the best devices constructed to date based on solution-processed organic materials, interpenetrating networks of soluble n-type semiconducting fullerenes such as [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) as electron acceptor and p-type semiconducting polymers such as poly(3-hexylthiophene) (P3HT) as electron donor moiety form the active interfaces. Such bulk heterojunction (BHJ) OPV cells have reached power conversion efficiencies (PCEs) of up to 6 %. [2] Despite their still lower PCE of around 4 %, solution-processable small-molecule-based BHJ solar cells are becoming increasingly attractive. [3] Owing to their simple purification and accessibility, paired with their monodispersity and ease of modification, small p-type organic semiconductor molecules have overcome many drawbacks associated with their polymer pendants.[4] While established p-type organic semiconductor molecules, for example, oligothiophenes, [3a,b] triarylamines, [3c] and acenes, [3d] were employed in initial BHJ cells of this type, recently traditional colorants such as merocyanines, [5a] squaraines, [5b] and dipyrromethene boron difluoride (BODIPY) [5c] dyes have been introduced, achieving PCE values of up to 1.7 %. As such chromophore-based materials can be easily optimized, particularly in regard to absorbance in the highly desired red and near infrared (NIR) spectral region where the solar photon flux culminates, [6] improvement of tandem devices [2a] and realization of transparent photovoltaic systems as demanded for the application on window glass are further opportunities that might arise from such small-molecule NIR-absorber materials.Squaraine dyes are a particularly promising class of chromophores for NIR OPV cells. They exhibit sharp and intense absorption bands in the desired long-wavelength region and possess considerable photo-and thermal stability under ambient conditions. [7] Thus, squaraines are a widely used class of functional dyes for a huge variety of applications.[8] Squaraines have been used in single-layer OPVs and, more recently, in vacuum-deposited and dye-sensitized solar cells.[9] Lately, Silvestri et al. reported for the first time on the use of squaraines in solution-processable BHJ solar cells with PCEs of up to 1.2 %.[5b]Herein we report on a series of squaraine dyes 5 a-e (Scheme 1) bearing an additional dicyanovinyl acceptor moiety at the central acceptor unit; these species afford solution-processed BHJ solar cells with PCEs of up to 1.79 %. More importantly, absorption in the highly desired NIR range and short-circuit current densities up to J SC = 12.6 mA cm À2 are achieved with these squaraines. ...

A platinum-beryllium adduct (see structure) was prepared by the reaction of [Pt(PCy(3))(2)] and BeCl(2). Treatment with methyllithium resulted in ligand substitution at the beryllium center. Both complexes were structurally characterized and display unprecedented two-center two-electron bonds between a transition metal and beryllium.

Dative bonds between transition metals and the archetypal Lewis acid BF 3 were proposed as early as 1966, [1] but were called into question 30 years later.[2] However, more recent work by Hill, [3] Parkin, [4] Bourissou, [5] and Rabinovich [6] and respective co-workers has demonstrated that borane complexes of the type [L n M À BR 3 ] [7] can be obtained from a range of late Lewis basic transition metals, and the nature of the dative metal-boron bond has been elucidated by experimental and computational studies. In addition, the metal-phosphine fragments {M(PCy 3 )} (M = Pd, Pt) have proven to act as versatile metal bases towards a range of coordinated boryl [8] and borylene ligands. [9] The heavier Group 13 elements are also known to form a variety of transition-metal complexes, in analogy to boron.[10]

The reaction of [Pt(PCy 3) 2] and GaCl 3 resulted in quantitative formation of the adduct [(Cy 3P) 2Pt-GaCl 3], the first known platinum gallane complex. Although similar reactivity with GaBr 3 and GaI 3 was expected, NMR spectroscopic data revealed a different reaction course. Crystal structure determination proved that, in the latter case, the product of the oxidative addition was formed. The resulting platinum gallyl complexes represent the first example of an oxidative addition of gallium(III) halides to low-valent transition metals.

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The platinum(0) monocarbonyl complex, [(Cy(3)P)(2)Pt(CO)], was synthesized by reaction of [(Cy(3)P)(2)Pt] with [(η(5)-C(5)Me(5))Ir(CO)(2)] and subsequent irradiation. X-ray structure analysis was performed and represents the first structural evidence of a platinum(0) monocarbonyl complex bearing two free phosphine ligands. Its corresponding dicarbonyl complex [(Cy(3)P)(2)Pt(CO)(2)] was synthesized by treatment of [(Cy(3)P)(2)Pt] with CO at -40 °C and confirmed by X-ray structure analysis.

Electron‐deficient borole compounds exhibit a pronounced Lewis acidity that is enhanced due to their antiaromatic character so that even weak donors datively coordinate to form Lewis acid–base adducts. This contribution presents the synthesis and structural characterization of Lewis acid–base adducts formed by the reaction of 1‐mesityl‐2,3,4,5‐tetraphenylborole and 4‐picoline as well as 1‐chloro‐2,3,4,5‐tetraphenylborole with various donors. The new compounds are characterized by means of multinuclear NMR spectroscopy and single‐crystal X‐ray diffraction techniques and compared to related systems.

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